Glutathione peroxidase 2 overexpression promotes malignant progression and cisplatin resistance of KRAS‑mutated lung cancer cells

Kirsten rat sarcoma viral oncogene homolog (KRAS) aberrations frequently occur in patients with lung cancer. Oncogenic KRAS is characterized by excessive reactive oxygen species (ROS) accumulation, thus, ROS detoxification may contribute to KRAS‑driven lung tumorigenesis. In the present study, the influence of glutathione peroxidase 2 (GPX2) on malignant progression and cisplatin resistance of KRAS‑driven lung cancer was explored. The RNA sequencing data from TCGA lung cancer samples and GEO database were downloaded and analyzed. The effects of GPX2 on KRAS‑driven lung tumorigenesis were evaluated by western blotting, cell viability assay, soft agar assay, Transwell assay, tumor xenograft model, flow cytometry, BrdU incorporation assay, transcriptome RNA sequencing, luciferase reporter assay and RNA immunoprecipitation. In the present study, GPX2 was upregulated in patients with non‑small cell lung carcinoma (NSCLC), and positively correlated with poor overall survival. Ectopic GPX2 expression facilitated malignant progression of KRAS^G12C‑transformed BEAS‑2B cells. Moreover, GPX2 overexpression promoted growth, migration, invasion, tumor xenograft growth and cisplatin resistance of KRAS‑mutated NSCLC cells, while GPX2 knockdown exhibited the opposite effects. GPX2 overexpression reduced ROS accumulation and increased matrix metalloproteinase‑1 (MMP1) expression in KRAS‑mutated NSCLC cells. In addition, GPX2 was directly targeted by miR‑325‑3p, while MMP1 knockdown or miR‑325‑3p overexpression partially abrogated the effects of GPX2 in NSCLC cells. In conclusion, the results indicated that GPX2 facilitated malignant progression and cisplatin resistance of KRAS‑driven lung cancer, and inhibition of GPX2 may be a feasible strategy for lung cancer treatment, particularly in patients with active KRAS mutations.

SATB1 protein is associated with the epithelial‑mesenchymal transition process in non‑small cell lung cancers

Lung cancer is one of the most frequently diagnosed neoplasms and the leading cause of cancer‑related mortality worldwide. Its predominant subtype is non‑small cell lung cancer (NSCLC), which accounts for over 80% of the cases. Surprisingly, the majority of lung cancer‑related deaths are caused not by a primary tumour itself, but by its metastasis to distant organs. Therefore, it becomes especially important to identify the factors involved in lung cancer metastatic spread. Special AT‑rich binding protein 1 (SATB1) is a nuclear matrix protein that mediates chromatin looping and plays the role of global transcriptional regulator. During the past decade, it has received much attention as a factor promoting tumour invasion. In breast, colorectal and prostate cancers, SATB1 has been shown to influence the epithelial‑mesenchymal transition (EMT) process, which is thought to be crucial for cancer metastasis. The aim of this study was to analyse the possible correlations between the expression of SATB1 and major EMT‑associated proteins in NSCLC clinical samples. Additionally, the impact of EMT induction in NSCLC cell lines on SATB1 mRNA expression was also investigated. Immunohistochemistry was used to assess the expression of SATB1, SNAIL, SLUG, Twist1, E‑cadherin, and N‑cadherin in 242 lung cancer clinical samples. EMT was induced by TGF‑β1 treatment in the A549 and NCI‑H1703 lung cancer cell lines. Changes in gene expression profiles were analyzed using real‑time PCR and Droplet Digital PCR. SATB1 expression was positively correlated with the expression of SNAIL (R=0.129; P=0.045), SLUG (R=0.449; P<0.0001), and Twist1 (R=0.264; P<0.0001). Moreover, SATB1 expression significantly increased after in vitro EMT induction in A549 and NCI‑H1703 cell lines. The results obtained may point to the role of SATB1 as one of the regulators of EMT in NSCLC.